


a malignant devil.

by silhouette (thiefless)



Category: Iron Man (Movies), Marvel Cinematic Universe, Spider-Man (Tom Holland Movies)
Genre: Adult Peter Parker, Angst and Tragedy, First Kiss, Grief/Mourning, Hurt Peter Parker, Leukemia, M/M, Metastatic cancer, Protective Tony Stark, Tony Stark Has Issues
Language: English
Status: Completed
Published: 2020-07-11
Updated: 2020-07-11
Packaged: 2021-03-05 05:21:11
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 1
Words: 3,339
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25209118
Author URL: https://archiveofourown.org/users/thiefless/pseuds/silhouette
Summary: It was a beautiful day: perfect in every single way....a beautiful day that ended in Peter Parker clutching his middle in pain, looking up with eyes blown wide in mangled terror, spitting, “Mr. Stark, I don't feel so good.”--Peter is diagnosed with radiation-induced cancer.
Relationships: Peter Parker/Tony Stark
Comments: 21
Kudos: 97





	a malignant devil.

**Author's Note:**

> This is just a bucketload of angst waiting to be served. I'm apologising in advance. Peter's age in this is somewhere between 18 and 21. The title is a from a quote from _Frankenstein_ : "But it is even so; the fallen angel becomes a malignant devil."
> 
> I hope you all enjoy it! I feel strangely nervous about uploading this. :)

It was a beautiful day – the kind poets penned beautiful lines to; the kind musicians composed harmonious devotion to; the kind scientists tinkered, brainstormed, invented miraculous conceptions to. Just because.

(No, Tony's opinion was not, in any way, shape or form, dependent on the fact that Peter was currently spending the day with him. What a ludicrous notion.)

“Hey, Mr. Stark,” Peter said cheerfully, strolling into the lab like it belonged to him. It was criminal how fast Tony's heart ran at the sound of his voice.

Tony prided himself on reigning in the surge of emotion Peter's entrance provoked. “Kid.”

Peter's smile widened at Tony's faux-neutral greeting, mischief dancing in his eyes as though he knew his ploy. 

Tony grinned back, and together they worked in flawless tandem on their respective enterprises, perfectly content in the other's company, speaking in a shorthand only they could decipher.

It was a beautiful day: perfect in every single way. 

...a beautiful day that ended in Peter Parker clutching his middle in pain, looking up with eyes blown wide in mangled terror, spitting, “Mr. Stark, I don't feel so good.”

* * *

Tony entered damage control mode, steering Peter to the nearest lab bench before gathering all the medical supplies F.R.I.D.A.Y. insisted he kept around the lab. _For_ _a_ _rainy_ _day_ , she'd said; her exact words. 

This was– 

This had all the hallmarks of a rainy day.

 _“Is he strong? Listen bud, he's got radioactive blood,”_ Peter sang. Correction: tried to sing. Mid-way through, he was overtaken by a hideous coughing fit that had Tony's own lungs seize in sympathy. “Who would've thought that song was ahead of its time?”

“Stop talking,” ordered Tony, rough and harsh. He cleared his throat, amended, did his best to convey the picture-perfect personification of calmness – it was a work in progress: “Please. I'm trying to think.”

Dutifully, Peter kept his mouth shut for the duration of the exam. His skin was warm where Tony touched, his every nerve raw. But Peter's silence didn't make the thoughts stop reverberating in Tony's skull. Pretty soon they'd induce a concussion, battering away in his brain. 

“It's cancer,” were the next godforsaken words out of the kid's mouth. 

“Quiet!” snapped Tony. 

“It's cancer,” Peter repeated, subdued. 

Tony refused to entertain the notion. Once he sent the blood off for F.R.I.D.A.Y. to analyse, he sent Peter to lie down. _Take my room,_ he said. Were it under any other circumstances, he would be thrilled. 

All he wanted to do was sob. 

* * *

Here's the rub: it was cancer. 

* * *

Tony trashed his lab when the news was broken to him – beakers and tubes smashed into walls; chairs overturned, splintered and wrecked; discarded paperwork shredded and mangled beyond all recognition. 

(Contrary to popular belief, even Iron Man did not escape unscathed from Tony's wrath.)

When all was said and done, Tony lay in the ruins of his safety net, and summoned the courage to re-read the report:

_Cancer. Radiation-induced. Acute myeloid leukaemia. Five-year survival rate: estimated at about 20%._

He went straight back to breaking his lab in two. 

* * *

“I don't want to tell anyone,” Peter murmured quietly the next day, eyes downcast. “Is that terrible of me?” he asked, anointing the Merchant of Death as his judge of morality; begging for an absolution. “Is that selfish?”

Tony had lost the power of speech since Peter's diagnosis, but if he had regained control long enough, he might have said something like: _No, Peter. Because all I want is to hold you in my arms for the rest of your life._

How was that for selfish?

Instead, he said, “You can stay with me for as long as you want. I'll keep your secret.”

* * *

Extremis was Peter's best option, best hope for survival. Not as it was, though; no, Tony would have to recalibrate the formula to match Peter's biology, to attack the malignant cells growing and eating away at him from the inside out.

Good thing Tony was a genius.

Helen started Peter on a high-dose course of chemotherapy, sustaining his life, keeping him alive long enough for Tony to perform a Hail Mary. A bone marrow transplant was out of the question. The risk of rejection was disproportionately weighted against him. 

It was an exercise in keeping his hands steady, drawing Peter Parker's blood. He had five vials full of the radioactive stuff already – by his reckoning, three would be ample to conduct experiments with Extremis; the other two would be for practice.

Peter's eyes were like dumbbells weighing down his soul, watching his face as he took the blood from him like some kind of vampire-scientist. The quiet was unnerving, but Tony didn't have the presence of mind to ask for inane chatter.

For the life of him, Tony didn't know why, yet he had a good feeling re: Peter's prognosis. He figured – with all the grief life had thrown at him, he had to be owed something _good_. Wasn't there some kind of law of averages to that effect? Yeah. Peter deserved to live, and Tony deserved for Peter to live. 

There, see? Two-to-one. 

Tony was built like a supercomputer. Scratch that: a super-super-computer. Like the ones NASA employed to check the legibility of people’s theories and equations – only Tony was smarter. Obviously. At any given time, he had exactly 367 tabs open, giving him the gift of knowledge; all he had to do was click on it, and absorb the knowledge as it was presented to him. (Just call him Sherlock Holmes.)

Poetic license aside, Tony was fucking incredible at what he did. He was gifted at everything; was a natural at everything. Chances were, if something stumped him, he would solve it within twelve hours.

Yep. He was Just That Good™.

Which was why he knew that he would cure Peter too. 

Besides, Peter always was deceptively strong. He could survive this. He had to. 

Because: Tony didn't know what he would do if Peter didn't. 

* * *

Thing was: Tony'd been through this before – he'd lost the kid, and fixed the kid. Yeah, it was the most painful experience of his relatively long life, but it should have been familiar territory for him; old hat. 

But, no. Peter's illness, so heartbreakingly _human_ in origin, ripped Tony apart at the seams far greater than the shit Thanos hurled at him. 

Cancer: the one mutation even the X-Men feared. Even Professor X deemed Peter a palliative case. 

But Tony Stark, Charles Xavier was _not._

Peter deserved the very best of the best; much more than some– some– some– meagre scientist, some quack, some person who was not Tony Stark.

Anyway, the kid was the very definition of an underdog. He'd survived countless hardships, and still managed to smile. He was Tony's better in every way. 

(Ergo: there was no chance in hell that Tony was going to allow Peter to die on his watch.)

Tony would repent to whatever deity commanded that of him; would beg and plead and live in whatever purgatory God or whoever else demanded for him.

Bottom line was: he would do anything to keep Peter alive.

Whatever it took. 

For days at a time, Tony occupied the lab, working tirelessly, to the bone, on his miracle. There, in the lab where he made beautiful creations every single day, he existed in the realm of liminality, where time and space ceased to hold any meaning – where Tony could determine his own past, present and future, constructing a make-believe timeline in which Peter didn't get sick, could never get sick, where Peter was with him, working in the lab on the latest web-shooter project or making amendments to the Iron Man armour and–

Until F.R.I.D.A.Y. pulled the plug on his peaceful ruminations, snapping him back into the cold harsh light of reality. 

“ _It's_ _Peter_ ,” she said quietly, and Tony, wearing a questionable three-day old concoction of musk and sweat like a Paco Rabanne cologne, dashed to his room that Peter had since taken residence in. 

Peter was seizing. 

* * *

Tests came back. 

The cancer metastasised to his brain. 

* * *

Low-rent Harry Potter himself reviewed Peter's MRI, his CT scan, at Tony's behest. 

His prognosis was one word: “Inoperable.” The polysyllabic diagnosis triggered a surge of angry anxiety in Tony's brain chemistry, quelled only by Peter's tentative hand on his arm. 

“I'm sorry,” Strange added. Sympathy was unbecoming on him. It was vaguely nauseating. 

They left Hogwarts in muted shock. 

“Maybe ‘m just not meant to live that long,” Peter joked, shrugging a half shoulder. His trademark characteristic joviality always covered up his true feelings; concealed, dressed up like a Spider-Man guise.

Pain radiated down the length of Tony's left arm at the kid's piss-poor attempt at a joke, singeing every nerve ending in its wake. He turned to stone. 

Peter looped his fingers through Tony's bad hand, and did not speak another word. The silent support was comfort enough. 

* * *

Tony modified Extremis several times over the course of Peter's treatment. At this point, it was his _pièce_ _de_ _résistance_. His swan song. 

Peter spat fire the first time. 

“Um,” he said, eyes caught in dazzled shock. “Is that supposed to happen?”

It was a work in progress. He went back to the drawing board.

Tony awoke one morning, as rested as he dared – a blanket draped over him, and a glass of water placed on the adjacent desk. 

Even dying, Peter took care of him. 

* * *

While Tony's progress plateaued, stagnated, Peter's cancer metastasised, mutated.

The spider that granted him his powers had also condemned him. Where the fuck was fairness?

Fact of the matter was this: Tony could do anything. 

* * *

Anything–

_except cure the greatest person the universe had ever known._

* * *

Peter's liver was the next to fall. Chemo could only do so much, even one tailored specifically to Peter's needs. 

“Mr. Stark,” Peter said, voice trembling minutely, barely hanging on. 

“It's okay, kid,” Tony said, his hubris ringing false. “I'm gonna make it okay.” He thought he heard Peter call after him, but his brain lacked the capacity to properly register it. He needed to hurry – and fast. Peter's life was on the line.

But all he could ask was: why?

* * *

Peter's body just kept waving the white fucking flag, yielding under the sadistic corruption of cancer. Tony wanted to scream, to curse, to blame, because how _dare–_

Just: how fucking dare.

* * *

Tony would compromise on a lot of things; he wasn't proud of it, but it was nonetheless true. _Peter_ was not one of them.

So, he got back to work. 

Time blurred into one single, solitary stream of consciousness.

Peter came down to the lab, walking on an unsteady gait, Tony reflexively holding him upright. 

“I think we.” Peter bit his lip, melancholy etched onto the porcelain features of his face. “I think you need to stop.”

When his brain finally processed Peter's request, Tony saw red. “How can you be so selfish?” The ferocity of the words barrelled through him, and even Peter looked taken aback. 

“I'm not being–”

“Oh, yes you are. I am working my ass off trying to keep you alive and, what, you're just ready to kick the bucket after a couple of little setbacks?”

Determination bled into Peter's stance, imbuing a conviction in him Tony had long since admired from afar. “Little setbacks?” he repeated, incredulous. “I have cancer in my liver, in my brain. It's in my _blood._ ”

“And I'm working on that!” Tony snapped, body jerking as if under attack. “You just gotta give me a second, here.” Anxiety coiled in his gut, his breathing became choppy and laboured.

Something dawned on Peter. Tony couldn't face him any longer. 

“Please, kid,” he whispered. “Please, just give me a second. Let me fix you.”

Peter's arms came to wrap around his middle, and he hooked his chin on Tony's shoulder – a pillar of utmost strength holding Tony upright. 

“Okay,” Pete whispered, lips brushing the shell of Tony's ear. 

Neither one of them left that fragment of a second for the longest time. 

* * *

Tony kept failing, failing, _f_ **a** _i_ **l** _i_ **n** _g_

–and Peter kept DYING in his arms: over and over and over again. 

* * *

One day, miraculously, Tony cracked the theorem. The newly-configured Extremis was injected into Peter's shot veins, Tony listening, attentive, at every rasp of the kid's breath, watching for any sign of resurrection. 

And then– oh, then Peter _breathed._ Exquisitely deep, majestic inhalations, filling the kid's lungs up with gorgeous oxygen, spitting out the carbon dioxide dregs. 

Peter turned to him, face split in half at the force of his grin, rapturous wonder lighting up the warm brown of his eyes, as animated as Tony had ever seen them. 

Driven by a fierce, inexplicable, deep-seated urge to kiss Peter until his lungs were shredding, until his mouth was red and swollen, until he could barely dissect where each of them began – Tony did so. Peter's tongue was warm and wet and inexpertly brushing against Tony's own, but he didn't mind. Au contraire: he _relished_ Peter's enthusiasm, encouraging him to shove his tongue down Tony's throat. Tony was perfectly content to allow Peter and his gloriously renewed strength to take charge. 

Peter laughed into Tony's mouth, and Tony grinned back, teeth clashing and noses banging, and neither of them giving a single fuck. 

* * *

Hands down: the best day of Tony's considerably aged life. 

* * *

Later that night, Tony woke up to Peter choking on his own blood, hand to his chin, eclipsed in a red darker than Iron Man. 

F.R.I.D.A.Y. ran his labs. Tony danced his fingers in the kid's sweat-kissed hair while he dozed in his lap, looking more peaceful than he had in a long time. 

Extremis performed seamlessly, flawlessly. Peter's white blood cell count doubled, tripled, quadrupled – stabilising at twice the rate of a normal human being. 

There was just one catch: Peter's blood developed antibodies.

“I can fix this,” Tony repeated, the mantra like a death kneel pounding in his head. “I can. You just gotta let me.”

Peter's fingers tremble as they stretch over the battered scar of Tony's heart. “I know you can,” he whispers, broken, and Tony wants to break down. “But I'm saying– I'm saying I don't want you to.”

Tony shook his head, refusing to bow, to buckle, to capitulate, because he was so close – oh, so very close – and he could do it, he could, he could do it, if only Peter didn't keep fucking dying long enough for Tony to fix him. 

Peter said, “ _Tony_.” – a breathless pardon.

Tony came apart.

* * *

Peter's eyelashes tickled the flesh of Tony's shirtless stomach. 

“I made.” Peter's body trembled under coughs. Tony's fingers tightened in his hair. “I made recordings. Videos, for everyone. Can you–”

Tony wanted to cry. “I’ll make sure they get them, sweetheart,” he whispered, as soft as he never allowed himself to be _before_. 

With a sigh, Peter melted into Tony. “Thank you.”

Tony's eyes felt like fire, like burning, as they drowned – a terrible oxymoron. _Don't thank me, kid. Please don't thank me_ , he would have said if he had a voice. 

“I'm sorry, Peter,” he managed to spit out amidst an overwhelming wave of grief; wet and choked. 

“Not. Your. Fault,” Peter replied, his assertion punctuated by short, sharp breaths, and that was how, without any basis in science or reason, Tony knew: Peter didn't have long left. 

_It should have been Tony, it should have been Tony, it should have been Tony–_

“You're going to be fine. You have to be, because.” Tony faltered, thick. He started again: “I haven't taken you out on a date yet.”

Peter's breath hitched. “A date?”

“Yeah, baby,” Tony whispered, pained with heartbreak, tinged with an optimism that would never come to fruition. “How about it? You, me, fancy restaurant, all the food you can eat. Hey, I'll even throw in a thousand-dollar bottle of wine that you are definitely too young to drink.” Tony clamped his lips down, fighting the urge to break down when Peter needed him to be strong. “It'll be our little secret.”

“Can.” Shivers wracked down the length of Peter's spine. Tony brushed what he hoped was a soothing hand down his vertebral column. “Can we do it tomorrow? I'm too. Tired. I want to be able to enjoy...” Peter's life refused to be sustained by the fumes of Tony's love. 

Tony's heart shattered in his throat. “Of course, we will,” he managed to whisper, unable to master autonomy over his vocal cords. 

Peter sighed, pleased. Content. _Dying_. “It's a date, then.”

This time, Tony's breathing became laboured, choked. Peter grappled for his hand, squeezing it as hard as his body would allow – not even a fifth of what he used to be able to do. Tony squeezed back. 

There, Tony held him, tracing three little words in the thinning scalp of the person Tony cherished above all else. He held him. 

There, Tony held him as he died.

* * *

Peter left Tony a video; a message from beyond the grave. No, he had not played it yet. For all intents and purposes, those words were the very last Tony would ever hear Peter speak. He just hadn't mustered the courage, yet, to fully comprehend that fact. 

When Peter...when he _left,_ Tony couldn't find it in himself to leave the relative safety of his lab. The one place he and Peter cherished together. The outside world had darkened, unable to sustain its vibrancy without the one person single-handedly responsible for it. What was the point in living in a box labelled 'reality' when his paracosm was so much more appealing?

Anyway, Tony and solitude went way back; their history was written with ancient ink, relationship fraught with bad coping mechanisms and an overdependence on alcohol – only the former of those were true nowadays, but the temptation was always there. Always. All Tony needed was a reason.

But Peter was reason enough to refrain. Even in his absence, he was still shaping Tony into being a better person. 

Tony occupied Peter's spot in the lab. It was the only place in the whole fucking universe where the thoughts buzzing around in his head – accusatory, hateful, self-doubt – quieted into, not quite tranquillity, but the closest Tony'd ever known it. It made him feel like...maybe a part of Peter was imprinted on the furniture, on the woodwork of the table; like, maybe a little of Peter's soul remained with him, there. 

At least– Tony chose to view it like that. 

May blamed him. Tony couldn't blame her for the knee-jerk reaction. Whether it was for failing Pete or failing to convince him to let his loved ones know the truth about his diagnosis, he didn't know. Not that it really mattered. Nothing really mattered anymore. 

He hoped the video Peter left May gave her some small degree of comfort in this horrifying, fucked up world they still existed in, because they still did and Peter did not. 

Tony thumbed his own recording. Pete had recorded his on an old VHS tape – and there was no doubt a pun in there about Tony being an old man. He wanted to press play, to watch. 

And _yet._

Rebuilding his heart from scratch was a long, arduous process – a trying task. Listening to Peter talk, his very final words, could either make or break him. Irreparably. There was a certain finality laden in there that should not be understated. 

God. Even seeing the kid's face – his handsome mannerisms, his charming vocabulary; his beauty, his smile; his bravery, his good heart – would kill him, would save him. The binary opposition was left in an ambiguous state. There was no telling which side it would fall. 

But Tony _missed_ him. It was an ache that would never quiet, would never be tempered. Gathering himself, he took a breath and hit **PLAY**.

* * *

**Author's Note:**

> Hey. Let me know what you guys thought of this. :)


End file.
